Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Kim, Sangtae [1], Lee, Bora [2].

Expression of floral MADS-box genes in Carex dickinsii Franch. & Sav. (Cyperaceae).

  The ABC(D)E model of floral MADS-box genes explains the genetic control of sepal, petal, stamen, and carpel identities in Arabidopsis, which is a model plant in eudicots. Only a few cases have been reported regarding the application of this model (or modified model) in monocots, for example, applications in maize and tulip. Carex is one of the largest genera in Cyperaceae, containing approximately 2,000 species. As a highly diverged group in monocots, evolutionary-developmental studies of floral MADS-box genes in Carex will provide a key to understanding the evolution and diversification of flowers in Cyperaceae. The floral structure of Carex is very different from that of Arabidopsis, and it is difficult to address the morphological homologies between floral organs of Carex and Arabidopsis. In particular, the evolutionary origin of specialized organs in Carex is questionable. These are 1) the perigynium, a sac-like structure surrounding the carpels and 2) the scales of the male and female flowers. To address these questions, we screened floral MADS-box genes in C. dickinsii and the expression pattern of each floral gene in each flower part in C. dickinsii is compared with that in Arabidopsis. The expressions of two B-class genes (Ca.di.DEF and Ca.di.GLO) and an E-class gene (Ca.di.AGL2) were restricted in the stamens and pistillate/staminate scales of mature flowers, respectively. The A-class gene (Ca.di.SQUA) and the C-class gene (Ca.di.AG) were not expressed in any of the mature floral organs. Instead, these genes were expressed in young female/male inflorescences (Ca.di.SQUA) and young female inflorescences (Ca.di.AG), indicating that the expressions of these genes decrease during the maturation of the flowers. The ABC(D)E model of floral organ identity is not strictly applicable to C. dickinsii because the expression patterns of its floral genes are somewhat different from those in Arabidopsis. We hypothesized that pistillate/staminate scales are parts of the flowers in Cyperaceae or at least that Ca.di.AGL2, an orthologue of the floral organ identity genes in Arabidopsis (AGL2), is involved in the identification of the pistillate/staminate scales in C. dickinsii. There is no evidence of the involvement of ABC(D)E-class genes in the organ identity of perigynium, which is a specialized organ in Carex, indicating the origination of the vegetative organ (bract) of the perigynium.

1 - Sungshin Women's University, Department of Biology, Seoul 136-742, Rep. of Korea
2 - Sungshin Women's University, Department of Biology, Seoul, 136-742, Rep. of Korea

Keywords:
Carex dickinsii
Cyperaceae
MADS-box
ABC(D)E model
gene expression.

Presentation Type: Oral Paper:Papers for Topics
Session: 41
Location: Payette/Boise Centre
Date: Wednesday, July 30th, 2014
Time: 2:15 PM
Number: 41004
Abstract ID:572
Candidate for Awards:None